The invention relates to a rim provided with rim flanges and a method for producing such a rim, in particular of a fibrous composite material.
In the field of amateurs in particular many bicycle rims comprise rim flanges between which a tire can be attached to the rim. In the field of professional cycling and again in the field of amateurs, the weight and the stress tolerance of the components are a decisive factor since quality-conscious users set great store by high-quality, lightweight components.
In the prior art, rims of fiber-reinforced plastics have been disclosed by means of which the rims may be reduced in weight. Concurrently these rims, while being reduced in total weight, achieve a stability comparable to that of metal rims. One drawback of rims of fiber-reinforced materials is the complicated production since many production steps must be performed manually which increases the costs.
Many rims are produced by way of positioning resin-impregnated woven fiber mats in a mold wherein after curing, finishing is required at least in the region of the rim flanges to give the rim flanges the desired shape.
For example EP 1 231 077 B 1 has disclosed a method for producing a rim for a bicycle and a corresponding apparatus for producing a rim according to which, to produce a hollow rim provided with rim flanges, multiple layers of a structural woven fiber which includes a plastic matrix, are successively, one by one applied on the inner part of a mold. The applied, predetermined quantity of layers forms the inner wall, the outer wall, the two side walls, and the rim flanges of the rim. Subsequently an inflatable bag is applied on the layers. A predetermined quantity of layers is folded back on the bag. A core is positioned on the folded back, first layers, the remaining layers being folded on top. After closing the mold, said mold is heated up to an increased temperature to generate reticulation of the plastic matrix. The rim is removed from the mold, overhanging rim flanges are trimmed and in a subsequent mechanical, cutting machining step given the desired shape.
A drawback of the known method is the high extent of work in producing the nm.
Therefore it is the object of the present invention to provide a rim and a method for producing a rim by means of which a lightweight though robust rim is provided while the production steps required are reduced.